Glass traps: Investigating bird mortality at glass-fronted buildings in the Nilgiris

Abstract Bird-window collisions pose a significant but underexplored threat to the avian biodiversity in India. This study, the first of its kind in the Nilgiris, South India, documents bird collisions with glass surfaces over a year. A total of 35 incidents were recorded across two locations, Forestdale and Coonoor, involving 22 species from 15 families. Among these, 16 birds were found dead, 18 were injured, and one managed to fly away. Migratory species, particularly the Indian Blue Robin, had the highest number of collisions, while among resident birds, the White-cheeked Barbet and Spotted Dove were most affected. Collisions peaked during winter, highlighting seasonal vulnerability. Building architecture, especially reflective glass surfaces, played a crucial role in increasing collision risks. These findings underscore the urgent need for mitigation measures such as UV-reflective films, window modifications, and strategic landscaping. Promoting bird-friendly urban designs and raising awareness are essential to reducing avian mortality in expanding human settlements.